It's not me... Linus Torvalds said !
Hence, the "U" in uniGUI will always have issues. And is not about filenames/folder name cases or paths only.
All browsers for Linux has issues. That's why all big corps using it always makes some rules regarding distros, browsers and what not's.
Another more deep explaining about it
Our company already has the development of GUI applications for Android, development for Linux (fmxLinux) is being prepared, I am putting together unigui projects for RHEL and Astra, at first glance it looks more complicated and you catch SegFault and similar errors, over time, withstanding the requirements of Linux, you get used to everything and it looks ok.
There are no bad instruments, there are people who do not yet know how to prepare them-)